Hello,
512 MB of RAM on an Intel Mac will not go as far as it will on a PowerPC Mac.
Generally, many people are finding that they run out of memory faster on the Intel Macs due to Rosetta requiring more memory.
If you run any PowerPC programs, then Rosetta will automatically run and will use more memory. Rosetta translates PowerPC code into code that will run on an Intel processor. Basically stores the translated code in memory while the program is open, and will cause you to run out of RAM faster due to the increased memory requirements.
Also, the Intel Mac Mini will pull about 80 MB of RAM right off the top for your video system (64 MB of RAM + 16 MB for overhead). So, you actually start with around 432 MB of RAM on an Intel Mac Mini. And, in some situations more memory may be pulled for the video system.
So, that may factor into your experience.
PowerPC Macs do not share their system memory with the video system. So, you don't lose any memory for video RAM on an PowerPC Mac.
Likewise, PowerPC systems do not have Rosetta, and do not need it since they can run PowerPC programs without conversion. And, they can also run the newer Universal Programs as well.
So, in many situations 512 MB on a PowerPC will be more than adequate.
I've used our Mac Mini G4 with 256 MB of RAM, and it was more than enough for the more modest needs (e-mail, word processing, web browsing, etc.). My wife had no complaints about it at all.
I upgraded it to 512 MB of RAM, and that was adequate for most iLife tasks (iPhoto, iMovie, etc.).
But, I did eventually upgrade it to 1 GB of RAM for better performance with iLife.
So, I wouldn't have any reservations about running a PowerPC system with only 512 MB of RAM. If you intend to do a lot of Video Editing and such, then I would recommend at least 1 GB. But, for basic needs 512 MB is enough.
For an Intel system though, I would consider 1 GB to be required if you will be running multiple programs and any of them is a PowerPC program. But, you could still get by with 512 MB.
I hope this helps.
